1. Technical Field
The present invention relates to illumination apparatuses provided with light guiding plates and light-emitting elements, display apparatuses provided with such illumination apparatuses, and electronic devices provided with such display apparatuses.
2. Related Art
Of the various types of display apparatuses, liquid-crystal apparatuses include an illumination apparatus referred to as a “light guiding plate apparatus” and a transmissive or partially-transmissive display panel (liquid-crystal panel) disposed on top of the illumination apparatus in an overlapping manner on the side of the light-emitting surface thereof; in the illumination apparatus, a plurality of light-emitting elements are provided along the side-end surfaces of the light guiding plate that function as light-entry portions.
As shown in FIG. 9, in an illumination apparatus configured in this manner, a configuration is often employed in which a plurality of light-emitting elements 1089 are mounted on a light source substrate 1088 on one surface 1881 that opposes a side-end surface of a light guiding plate 1080, and the light source substrate 1088 is anchored to a substrate support plate portion 1062 using screws. At this time, when the screws are tightened from the side of the one surface 1881 of the light source substrate 1088, areas where the light diffusion characteristics are uneven arise in the one surface 1881 of the light source substrate 1088 due to differences in the surface states on both sides of the locations where the screws are disposed, in the lengthwise direction of the light source substrate 1088. As a result, unevenness in the brightness of the illumination light emitted from the light guiding plate occurs, resulting in a problem that the image quality is reduced.
Meanwhile, a structure in which through-holes 1625 are formed in the substrate support plate portion 1062 and the light source substrate 1088 is anchored to the substrate support plate portion 1062 by tightening screws 1086 into the substrate support plate portion 1062 from the opposite side as the light source substrate 1088 has been proposed (see JP-A-2011-40388, FIG. 13 and so on, and JP-A-2009-3081, FIGS. 2, 7, 10, and so on).
To realize this configuration, closed-ended holes 1885 that span to a position partway through the thickness direction of the light source substrate 1088 are formed from another surface 1882 of the light source substrate 1088, and the screws 1086 are tightened into the holes 1885.
However, as shown in FIG. 9, it is necessary to properly manage the depth of the holes 1885 in order to form those closed-ended holes 1885 that span to a position partway through the thickness direction of the light source substrate 1088 from the other surface 1882 of the light source substrate 1088, and thus a great amount of effort is required to form the holes 1885. In other words, as described above, if the holes 1885 are passed through the light source substrate 1088, the surfaces of the screws 1086 that pass through and are exposed on the side of the one surface 1881 of the light source substrate 1088 will cause differences from other surfaces in the light diffusion state, reflection state, and so on; this leads to areas of optical unevenness, which causes the uniformity of the illumination to be lost. Alternatively, there may be the risk that wires formed on the one surface 1881 of the light source substrate 1088 will become disconnected. On the other hand, if the holes 1885 are too shallow, the light source substrate 1088 will be pressurized by the screws 1086 when the screws 1086 are tightened down, resulting in the light source substrate 1088 deforming and the optical axes of the light-emitting elements 1089 tilting.